The present invention relates generally to a motor, and more particularly to an improved motor housing structure.
A conventional two-piece motor housing includes two cover shells, each of which is substantially a hollow cover body and has an annular stepped portion at an inner wall thereof and an axle hole at a bottom center thereof. A plurality of mounts are integrally connected with an outer periphery of the cover body and are substantially equiangularly arranged and respectively have a through hole or a threaded hole parallel to a longitudinal axle of the motor housing. In process of assembling, one of the cover shells is first sleeved onto an end of a cylindrical stator of a motor with the annular stepped portion engaged against an outer fringe of the end of the stator, and then a rotor of the motor is inserted into the stator by the way of an end of the rotor running out of the axle hole of the cover shell. And the other cover shell is fit with the aforesaid cover shell by inserting the other end of the rotor through the axle hole thereof and the annular stepped portion thereof engaged against the other end of the stator. The two cover shells clamp the two ends of the stator, and an outer periphery of the stator is partially exposed between the two cover shells.
In the process of being threadedly-engaged, since the mounts of the two cover shells are spaced in a predetermined distance, which is namely an exposed portion of the stator, operators have to fit the second cover shell to the first cover shell by rotating the cover shells to make the mounts of the two cover shells in alignment with each other and by inserting a screw into the through hole or the threaded hole, such that the two cover shells are threadedly engaged and are fit tightly with the stator. The operators have to carefully align all the mounts of the two cover shells with each other in the foregoing process, which works inconveniently and inefficiently.
Furthermore, the two cover shells are made by casting such that there is a dimensional deviation between the two cover shells. While the motor housing is assembled, the two cover shells are not entirely engaged and the stator is positioned between them and further there are dimensional deviations among different stators. Accordingly, a deviation of the distance between two ends of the two cover shells is a total amount of the two dimensional deviations of two cover shells and the stator, such that a length of the rotor extending out of the cover shells is variational and the precision of the motor goes down.
The primary objective of the present invention is to provide an improved motor housing, which facilitates and accelerates the assembling process to be timesaving and high productive.
Another objective of the present invention is to provide an improved motor housing, which has fewer deviation of the length between two ends of the motor housing and higher precision of the products.
The foregoing objectives are attained by an improved motor housing of the present invention, which comprises two cover shells respectively having a hollow cover body with an opening and mounts mounted on the outer periphery of the cover body. The present invention is characterized in that at least one of the two cover shells has at least two ledges, which protrude outwardly from an edge of the opening of the cover body. The mounts are respectively provided on outer sides of the ledges and respectively have a first matching portion at an inner side of the end of the mount of the first cover shell and a second matching portion at an inner side of the end of the mount of the second cover shell. The two matching portions are complementary in shape to be engaged with each other. The two cover shells are fit tightly with two ends of a stator of the motor, and the ends of the mounts of the two cover shells are contacted to each other in pairs and are fastened with each other by screws such that the two cover shells are firmly connected.